1. Field of the Invention
This invention relates generally to the field of gaming machines, and in particular, to a method and apparatus that detects fraud or theft in a coin-operated gaming machine by monitoring the weight, and therefore the number, of coins contained in and removed from the gaming machine.
2. Description of the Prior Art
Gaming machines such as slot machines are traditionally activated by a player inserting one or more coins or tokens into the gaming machine. If the player wins, coins or tokens may be paid out to the player. Recently, gaming machines have been modified to accept in addition to coins, paper currency, credit cards and bar coded credits. Though very popular, these alternate forms of currency have not eliminated the use of coins and tokens.
Generally, gaming machines that receive and dispense coins are provided with a coin drop box and a payout hopper. When coins are inserted into the gaming device, they are directed to either the coin drop box or the payout hopper. As the name suggests, the payout hopper holds coins that will be dispensed to the player if the player obtains a winning selection. The coin drop box holds excess coins that will be collected by the gaming machine operator. U.S. Pat. No. 4,238,127 issued to Lucero et al. discloses a gaming machine that senses the weight of the payout hopper and when the weight attains a certain threshold, coins inserted into the gaming machine are diverted to the coin drop box. This gaming machine allows the payout hopper to stay sufficiently full but prevents overflow of the payout hopper by diverting coins to the coin drop box.
As there is a constant inflow and outflow of coins through a gaming machine, it is extremely important to keep precise and accurate records of game activity. The gaming machine must accurately monitor the number of coins inserted into the gaming machine and must accurately payout the correct amount of coins won by the player. Accurate accounting is not only required for the gaming machine operator, but is also required by gaming regulations.
Standard techniques are used for automatically counting the number of coins inserted into a gaming machine and counting the number of coins paid out of the gaming machine. Two such techniques include using a mechanical trip device and an optical sensor device. Both devices essentially count the passing of coins either into the gaming machine or out of the gaming machine. Unfortunately, both the mechanical trip devices and the optical sensors are susceptible to fraud.
A technique of fraud commonly known as "stringing" can thwart mechanical trip devices. The technique of stringing and a device designed to overcome this fraud are described in U.S. Pat. No. 4,243,133 issued to Nicolaus. Stringing is accomplished by attaching a string to the coin inserted in the gaming machine and manipulating the coin with the string to make it appear that several coins were inserted.
Optical sensors were implemented to overcome fraud by stringing. An example of an optical sensing device is described in U.S. Pat. No. 3,998,309 issued to Mandas et al. The optical sensors, however, are also susceptible to fraud, especially at the point of payout. Optical sensors transmit a beam of light across a path along which coins may pass from a payout hopper to a payout receptacle. An interruption in the beam of light represents the passage of a coin. By placing a light emitting device in a position near the optical sensor, the operation of the sensor is interrupted such that the sensor does not detect the passage of coins, and therefore, does not signal the gaming machine to stop providing coins from the payout hopper. That is, by fraudulently manipulating the optical sensor, a player may receive a payout of the entire contents of the coin hopper. This obviously is not desirable for the gaming machine operator.
During the operation of the gaming machine, the payout hopper may become depleted and may need replenishing, or the coin drop box may become full and need emptying. In addition, the gaming machine may need to be inspected by various personnel. In these situations, the gaming machine operators' personnel need to gain access to the internal portion of the gaming machine, and in particular, may need to gain access to the payout hopper and/or coin drop box. Because both the mechanical and the optical sensing devices operate at the point of insertion and payout only, they are not useful in detecting direct bulk changes to either the coin hopper or the coin drop box. Therefore, these operations provide opportunities for employee fraud or theft.
In the fraudulent scenarios discussed above, the situation is further aggravated in that the fraud or theft may not be detected until substantially after it has occurred. Since gaming machines are generally found in abundance, such as in a casino, the perpetrator of the fraud will move from machine to machine to increase ill-gotten gains. Early detection of fraud decreases the perpetrator's chances of multiplying his gains.
Therefore, there is a need for an accurate and instantaneous system to monitor and prevent fraud in gaming machines.